4. Modern strategies

4.1 Reducing the waste of energy in trekking to water
4.2 Controlling the intensity, evenness and period of grazing
4.3 Factors that determine the appropriateness of adopting modern strategies

'Modern' strategies can be contrasted to 'traditional' ones; the latter have been defined principally in terms of their not requiring large inputs of skills, equipment or money from outside Africa. Modern strategies are, therefore, by implication ones which do require these exogenous inputs. The fundamental element in modern strategies is the new ability to place water points where one wants them to be rather than where, by accidents of nature, it is relatively easy to identify a local source of water and to extract it for use by livestock. This new ability depends on exogenous technical skills (hydrology, mechanical and civil engineering), equipment (drilling rigs, earthmovers, metal or plastic piping) and capital resources (e.g. loans from banks or donor agencies). An important determinant of whether this new ability is exercised is the balance between the costs and benefits of investment in water points. The economic considerations which touch on this balance are not discussed to any significant extent here, but may be reviewed by ILCA in a subsequent report.

Two main modern strategies exist. The first is to increase the spatial density of water points, so that the energy expenditure involved in trekking to and from water is minimised and so that the species, breed, and class of livestock kept can be determined by their relative productive ability rather than by their ability to cope with water shortage. The second strategy is to use the location and density of water points, and the dates at which they are opened and closed to use, as a principal means of controlling the intensity, the evenness (in space) and the period of grazing in the interests of optimal pasture productivity. The second strategy may involve the use of fencing to control the movement of livestock around water points. It is also related to the availability and amenability to direction of herding labour. In situations where herdsmen are hard to obtain the provision of a water point in each of many small paddocks may be an alternative to close herding for ensuring that pasture is used properly. Where herders are disinclined to heed verbal instructions on pasture rotation, the opening and closing of water points, by such means as removing parts of machinery or locking taps or access gates to dams or hafirs, may be a way of compelling the herdsmen's compliance. The technology involved in modern, as opposed to traditional, water points makes control by a centralized management over recalcitrant herdsman technically more feasible although in practice social pressures (e.g. bribery and coercion) often overrule technology. One observer of government water points in Niger has commented:

'Practically, herders and herd owners coerce the managers of pumping stations into opening the stations whenever the herders find them more convenient.' (Eddy, 1979, p. 168).

4.1 Reducing the waste of energy in trekking to water

It is very difficult to quantify in a satisfactory way the benefits which increasing the density of water supplies will bring through changes in the species, breed and class of livestock¹⁶. It is however possible, in a highly simplified model (explained in the notes to Table 4) to quantify the effects, for particular classes of animals, in terms of the extra energy made available for production, of reducing the energy expenditure on trekking long distances to water. The details of the calculations for lactating cows are shown in Table 4. The key assumptions, coefficients and parameters are drawn from King (1983, especially Ch. 5). Simplification is introduced by assuming that water frequency does not increase with greater density of water supplies and that body weight remains constant, i.e. that cows do not sacrifice body tissue in order to maintain milk output. Relaxation of these simplifications will not substantially alter the general picture, which is that a reduction in the spacing of water supplies (spacing = twice the maximum radius of the grazing circle), for example from 26 km to 20 km nearly trebles output (milk supply); but further reductions (in spacing of water supplies) lead to smaller proportional results, so that finally decreasing the spacing from 10 km to 4 km increases output by only an additional 9%.

16 For a review of some of the literature see Squires (1978b).

Table 4. Relationship between density of water points and energy available for production.

a R = rounded to nearest km.

^b G = = R/, rounded to nearest km; assumes watering every other day for all densities of water points. This is the formula for determining the radius of the inner ring where a circle of radius R is divided into two rings, an inner and outer, and where the surface area of the two rings is the same. This is a simplifying approximation to the correct formula for estimating average daily distance walked to water according to one model of how livestock will progressively utilise the grazing around a central water point.

^c Assumes intake varies with daily distance walked with a maximum intake (in DM) of 2.5% of body weight; the gross energy content of intake is 18 MJ.kg^-1 DM; digestibility 55%; metabolisability 81%. See King (1983, Equations 5.01 and 5.02).

^d ME = metabolisable energy.

^e 0.343W^0.73/efficiency of conversion; where W = liveweight = 250 kg and efficiency of conversion for maintenance is 0.68.

^f Prehension, tearing, eating at 40 kJ.MJ^-1 ME of intake.

^g Assumes that animals walk 10 km per day, on average, while grazing in excess of the daily average distance walked to water.

^h Energy cost of walking is 1.8 kJ ME.km^-1 .kg^-1 of liveweight.

ⁱ At this spacing of water supplies the animal loses weight at the rate of about 0.5 kg per day and will soon stop lactating.

^j At 3.6 MJ net energy per litre, with a conversion efficiency of 0.6, thus requiring 6 MJ ME to produce 1 litre of milk.

Table 5 shows the same general pattern in a different way. Using exactly the same assumptions as for Table 4 it shows in summary form how successively quadrupling the number of water points increases output as a consequence of the reduction in energy wasted trekking to water. Of course at the higher densities of water points some of the original assumptions, e.g. about distance walked while grazing, about watering frequency, about food intake, are no longer realistic. For example,

Table 5. How multiplying the number of water points increases output by saving energy spent on trekking water.

a Output per head of livestock (beast) in paddock size (A) less output in next largest paddock (B) as a proportion of output in paddock B is given by

Squires (1978b)¹⁷ has shown, for sheep, that food intake declines with increasing distance between food and water¹⁸, as does drinking frequency and, above a distance of about 5 km, total water intake. Moreover, the simplified model here ignores many of the trade-offs between intake, loss of weight, metabolic rate and distance walked (and the seasonal variations in these) contained in the more complex model used by King (1983). It represents, therefore, only a first approximation to reality on which we must rely until more direct empirical evidence, derived from pastoral systems, becomes available on the relation between distance and water and economic output. It is, nevertheless, illuminating in showing how initially large proportionate returns to reducing the spacing between water points (i.e. an increase of 34% in output as a consequence of halving the spacing from 20 to 10 km) rapidly falls off for successive proportionate reductions in spacing; so that the final halving in spacing from 5 to 2.5 km yields only an additional 2% in output.

17 Drawing on Squires (1970b), Squires and Wilson (1971) Squires et al (1972), Daws and Squires (1974).

¹⁸ A decline not closely associated with decreased time for grazing caused by wastage of time trekking to water.

4.2 Controlling the intensity, evenness and period of grazing

The second main modern strategy is to use water points as an instrument in controlling grazing and trekking in such a way as to increase the productivity of pasture and to minimise soil erosion. The density of water points, their location in relation to natural features such as hills, and the periods of the day or year in which they are open, influence the distribution and movement of livestock in space and time. On unfenced rangeland in Australia unherded cattle can be redistributed between different areas simply by closing one water point and opening another (UNESCO, 1979, p. 469). Where livestock are herded, the opening and closing of water points, and limitations on the supply of water from them, can be used to enforce pasture rotations and stock limitations against the wishes of the herdsmen. However, as we have already seen, and as is experienced frequently, a central management body's decisions about the operation of particular water points may not always be respected by their operators in the face of local pressures.

Livestock, with their attendant trampling and grazing pressures on soil and vegetation, are seldom evenly distributed across the landscape. Where water points are sparse, trampling and overgrazing normally occur in concentric rings of increasing intensity the closer one approaches to the water point. The relationship between distance to water and pressure may best be represented, diagrammatically, by a curve which is sigmoid in shape - not much change in pressure in the first band, then a very sharp change, tailing off further out - rather than simply linear (Graetz and Ludwig, 1978). One example of this spatial distribution of pressure in relation to the location of a water point is given in Table 6.

Similar data can be quoted to show how palatable vegetation is replaced by unpalatable vegetation as one approaches a water point.

A spatially more even distribution of pressure on vegetation and soil can be brought about by increasing the number of water points - although this may lead to an overall greater, albeit more evenly distributed, pressure - and by fencing or careful herding. Some livestock, e.g. sheep in mountainous areas, distribute themselves, unherded, more evenly than others, e.g. cattle (Stoddart et al, 1975, p. 285). Naturally the distance which livestock will graze out from an isolated water point varies by species and class of livestock, from place to place and season to season, and according to vegetation type and whether the animals are herded or not¹⁹. For example, around one water point (Mount Capitor Bore) in Central Australia the grazing distance from the water point of the majority²⁰ of cattle (unheeded) varied from 1 km to 13 km depending on season and grazing abundance (Hodder and Low, 1978). At another water point (Sandy Bore) in the same general area, faced with similar conditions of feed scarcity, at no time did the majority graze more than 8 km. In contrast, Table 7 shows the distribution of nomadic flocks in the dry season in arid Mali.

19 For a further analysis of factors affecting the spatial distribution of livestock see Squires (1976).

²⁰ In the original paper the expression 'majority' is not defined. Presumably it refers to a cumulative frequency of ³ 50% of cattle at all distances up to the one quoted; but some of the language of the paper suggests otherwise.

Table 6. The effect of gross overgrazing around a wet-season water point (Mare d'Arodouk) in Mali.

Source: Boudet (1977, p. 191).

Table 7. The spatial distribution of nomadic livestock in an arid zone in Mali.

Source: Swift (1979, p. 154).

The evidence is not conclusive, but it suggests quite strongly that herding is an alternative to extra water points as a way of obtaining a more even distribution of livestock across the landscape. No direct evidence is available to compare, other things being equal, the impact of such a livestock distribution on soil and vegetation resources in circumstances where herding is practised in contrast to those where it is not.

In smallholder dairy systems fencing and installing water supplies in fenced paddocks is primarily aimed at preventing disease-susceptible stock, on the way to water points, from entering land where they may pick up infections or parasites (Goldson, 1980). We could call this a third modern watering strategy. In drier areas fencing is another alternative to herding as a way of obtaining both a rotation of pastures and a more even spread of grazing pressure. Often fencing into paddocks will also require the installation of extra water points so that each paddock has its own supply and no trekking between paddocks in search of water is required. In Australia, Squires (1978a, quoting Squires, 1970a) suggests that sheep normally concentrate their grazing within a 3 km radius of water, and this would imply a maximum paddock size of about 3600 ha for a water supply centrally located in a square paddock²¹ (or 900 ha if located in a corner). The data already referred to in suggesting a sigmoid relationship between distance to water and grazing pressure (Graetz and Ludwig, 1978) suggest that about one tenth, in a ring at the centre of such a 3600 ha paddock, would be heavily used and the remainder would be under even pressure. For cattle, especially for Africa's relatively long-legged rangeland cattle, we can presume that a bigger paddock size would be appropriate. Squires (1978b) suggests that 4000 ha may be grazed by sheep, in Australian conditions, from a single water point, but 17000 hectares - a square paddock of 13 x 13 km - by cattle, a maximum radius of about 7 km.

21 The implication is that about 20% of the paddock in the corners outside the circle of 3 km radius would be underused.

Constructing separate water points for each paddock of 4000 ha involves very substantial capital cost per ha in water development. As an alternative to this, fencing can be used to channel livestock away from single water points further than they will normally graze of their own accord. Kilgour (1974) - quoted by Squires (1978b) - has suggested fenced lane-ways radiating out from permanent water and widening out into funnel-shaped fenced lanes ending beyond the normal grazing range of the livestock being managed. In southern Africa, in connection with the so-called Savory system of short-duration grazing, up to 30 or more fenced wedge-shaped paddocks radiating, like the spokes of a wheel, from a single water point have been advocated (Savory, 1975; Farmer's Weekly, 1976) for the ranching of cattle. However, it is not clear from these sources that more than 8000 ha can be served in this way from a single water point, although very even use of pasture and up to three times the normal safe stocking rate are claimed for this system.

4.3 Factors that determine the appropriateness of adopting modern strategies

It is evident from the previous discussion that the main factors that determine whether and to what extent one of the modern strategies reviewed here should be adopted will be the relative costs and prices of modern water technology (which is the key to adopting a modern strategy), economic output from livestock, fencing and herding labour. The first strategy discussed was an increase in the density of water supplies in order to reduce energy wasted in trekking to water. Successively quadrupling the number of water points (i.e. halving the distance between them) produces successively smaller proportionate (and absolute) increases in output. The cut-off point at which it will no longer be worthwhile to increase further the density of water points will be determined by the cost of additional development relative to the price at which the additional output can be sold. Similarly the second strategy, to ensure optimum intensity, period and evenness of grazing pressure, involves a careful weighing of the relative costs of water development, fencing and labour - all of them partly complementary, partly alternative means whereby grazing pressure can be controlled to increase economic output.

There are, however, some complicating factors that need to be taken into consideration in both the main modern strategies. One of these is that topography and the spatial distribution of soil and vegetation in Africa are seldom so uniform that livestock (or their herders) are indifferent about which direction they head away from the water point; nor is the distance they trek from water solely determined by the availability of metabolisable energy in the grazing. On the contrary, livestock feed very selectively and roam purposefully to areas where the vegetation they prefer grows. In Botswana:

'Significant portions of almost untouched pasture can be observed less than 1 km from water points even in the crowded eastern areas.' (Gulbransen, 1980, p. 199).

In Australia:

'Both cattle and sheep have been shown to walk long distances to reach preferred plant communities, often passing through abundant forage on the way.' (Squires, 1978b, p. 433).

Carefully planned spacing of water points that assumes tidy concentric circles of grazing pressure can lead to locating water points in a way that increases rather than reduces energy spent on trekking. Secondly, with this asymmetry in where livestock prefer to graze is an asymmetry in where it is cheapest to find water. Modern technology may make it possible to put in a water point almost anywhere - by piping in a supply if necessary; this does not alter the fact that it may be far cheaper to put a modern water point alongside a sandy river bed than 2 km away on a ridge, where symmetry may demand that it be placed.

The third complicating factor is that nowhere does a planner of water development (or fencing) start with a clean sheet. In almost all cases he will be faced with an existing pattern of spatial distribution of water points (this also applies to fencing). If they are evenly spaced so as to be in the right position for the present policy for locating water points, e.g. that they should be a certain distance apart, they will almost all of them be in exactly the wrong position for any new policy of more closely spaced water points; unless the new policy is to halve the distance between water points, which means quadrupling their number-an enormous investment. That may seem a very theoretical point but it is one that ranchers also find in practice, in respect of both water points and fences. In Australia:

'Management is often severely constrained by the siting of fences and water points. Paddock size, once determined, is not easily altered. Unless a fire removes a fence the next unit of subdivision is to split it in half; this may provide a second best approximation to optimum paddock size...' (Squires, 1978a).

In Zimbabwe the introduction of a short-duration grazing Savory system has been hampered where attempts have been made to graft it on to an existing layout of water points and fences (Savory, 1975) and complete replanning of existing ranches may be preferable (Savory, 1978), although it is obviously extremely expensive. Water points and fences cannot be uprooted and replanted in fresh places as easily as seedlings in a garden.

We can see, therefore, that as well as relative prices both the homogeneity of the landscape, in terms not only of the palatability of the vegetation but also of the cost of developing water in different places, and the extent to which new water developments are being imposed on an existing pattern that is at variance with a new policy, will be important in determining whether and to what extent the modern strategies will be taken up. Finally, part of our definition of a modern strategy is that it is dependent on exogenous inputs. Not only is the availability of such exogenous inputs unreliable, both in the development and in subsequent operating stages, but where they are introduced into traditional societies it is particularly difficult to predict how the benefits which will accrue from their introduction will be distributed between different interest groups. We return to this point in the next chapter.